In all split-and-merge techniques the fundamental problem is the initial segmentation. In this paper the initial segmentation is done by introducing the concept of rank of a point. The split-and-merge is done using two criteria functions, namely, the ratio of the arc length to the length of the line segment and the ratio of the distance from a point to the line segment (not the perpendicular distance) to the length of the line segment. The procedure generates polygons that are insensitive to rotation and scales and remains reliable in presence of noise. © 1995.